Biotecnologia e bioinsumos: desempenho fisiológico e produção de metabólitos secundários em tomate e alho

Abstract

This study investigated biotechnological strategies and bio-inputs to improve agronomic performance and secondary metabolite production in Allium sativum (cv. Ito) and Solanum lycopersicum (cv. Ibiza) under stress conditions. The study integrated the analysis of mineral nutrition and the use of bio-inputs as tools to increase plant resilience. In the tomato experiment, the efficacy of Azospirillum brasilense and Bacillus amyloliquefaciens in mitigating water stress (100%, 50%, and 25% supervision regulation) was evaluated. Water restriction hindered height and DNA content, but bacterial co-inoculation promoted significant increases in stem diameter, root length, and dry mass. Biochemically, the bacteria modulated redox homeostasis, increasing the activity of SOD, CAT, and APX enzymes, as well as influencing the accumulation of proline and photosynthetic pigments as an adaptive strategy. The interaction between surface viewing slides and inoculants also regulates the production of phenolics and flavonoids, reinforcing the role of growth-promoting bacteria in the physiological plasticity of the crop. In the experiment with garlic cultivated in vitro, the availability of sulfur (S) proved to be a determining factor for both the morphological development and the biochemical identity of the plant. The total absence of sulfur (0.0 g L-1 ) prevented bulb formation and significantly compromised total biomass, demonstrating that this nutrient is essential for the transition from vegetative to productive growth. A dose of 0.16 g L-1 was indicated as the optimum point for the accumulation of dry matter in the bulbs and for the development of superior morphological characteristics, such as greater area and diameter. Regarding the secondary metabolism of garlic, active sulfur acts as an essential precursor in the biosynthesis of thiosulfinates, whose levels in the bulbs gradually increased with supplementation, reaching a peak at a dose of 0.64 g L1. We observed a distinct modulation between growth and defense: while moderate doses favored biomass, a higher dose (1.28 g L-1 ) significantly potentiated the total antioxidant capacity (DPPH and ABTS) and the levels of phenolic compounds in the bulbs, evidencing a redirection of metabolic flow towards protective mechanisms under conditions of nutritional excess. Furthermore, S supplementation influenced the dynamics of total sugars and organosulfur compounds. The results show that mineral nutrition needs sulfur and the use of microbial bio-inputs are complementary pillars for sustainable and resilient agriculture for agricultural crops.